I have been doing a modified/updated version of Dr. Swank's diet since I was diagnosed in 2007, and I highly recommend giving it a serious look. By "updated" I mean that the recipes that form the 2nd half of Dr. Swank's book are very dated (think 1950s cooking...1980s at best), and I prefer a diet full of fresh organic vegetables, and occasional chicken breast (organic free range) or fish (many restrictions on which fish are safe to eat!).
It's not hard to limit your saturated fat intake to 10-15 grams per day...I am usually closer to 10g. Swank's recommended limit was higher. It takes some time to learn about different kinds of fats and how to make sure you're getting enough fat (the right kinds of fat).
One book I HIGHLY recommend is Professor George Jelinek, M.D.'s book, "Taking Control of Multiple Sclerosis: Natural and Medical Therapies to Prevent its Progression." You can find it on Amazon UK -- that's www.amazon.co.uk
, I believe. Jelinek, an MD whose mother had MS and who has MS himself, argues persuasively for the efficacy of the Swank diet, and references not only Swank's original research but also research that has been done much more recently that supports findings about the importance of low saturated fat in the diet, and of fish oil/fish supplementation. (If you are vegan, there is a vegan way to get the DHA that is in fish oil.)
And DO read what has been discussed already on this site. I find that this site is the most technically/scientifically savvy of all the sites I have found re MS.